Portable electronic and electrical apparatuses have ever increasing demands for their associated energy sources. The energy sources must combine a high level of energy, power and/or power storage with low weight and volume in order to allow portability of the apparatuses. These energy sources must also be cost efficient, operate over a broad range of temperatures, provide for a long shelf life, for long periods of charge or energy retention, and be safe to use, transport, and recharge.
There is an unmet need for capacitors or energy storage devices or apparatuses that combine the properties of high energy density (SN), high energy per mass (S/M), high cycle life (#), high charge or energy retention (RC or RE), the combination of high TUpper and low TLower and fire and explosion resistance at low cost. This currently limits the capabilities of portable electronic apparatuses resulting in less than desirable performance, cost, safety and environmental protection.
For example, batteries, such as rechargeable lithium batteries (RLiB) exhibit relatively high S/V (as high as ca. 900 Wh/liter) and S/M (as high as ca. 400 Wh/Kg), but suffer from relatively high TLower (ca. −10 C or higher) where battery discharge capacity is reduced by at least about 20% and do not operate below about ca. −20 C. Additionally RLiB have relatively low TUpper (ca. 50 C-60 C) as RLiB may become dangerous if used above 60 C, and thus are not recommended for use above 60 C. Further, RLiB batteries typically also perform relatively poorly with respect to charge and energy retention (RC or RE ca.≤50% retention over 180 days), as well as charge and discharge current capability (IC and ID≤1.2 C, where C is equal to the amount of current required to discharge said apparatus to its termination voltage in a 1 hour period), and explosion resistance and fire resistance; the latter two factors have limited their use and have caused risk to the public. Additionally, rechargeable batteries such as RLiB or the like, typically exhibit cycle life (#) performance of 2,000 cycles or less (more typically 1,000 cycles or less). These characteristics of rechargeable batteries, such as RLiB or the like, limit their usefulness and make them expensive over the long term, as they must be replaced after a few years or ˜2,000 charge/discharge cycles or less. Even the best rechargeable RLiB batteries are projected to have less than ˜1% of their initial charge capacity when approaching charge/discharge cycle numbers (#) of ca. 40,000 or more when charging/discharging at 1 C or higher. Further, most of these rechargeable battery devices or apparatuses are not recyclable or are difficult to recycle, and are not environmentally friendly as they may contain non-compliant and/or toxic substances that may result in harm to the environment.
Traditional capacitors, EDLCs, or supercapacitors also exhibit short comings. While they may exhibit satisfactory TLower and TUpper, as well as #, they typically suffer from relatively low C/V (ca. 10,000 F/liter or less), C/M (ca. 7,000 F/Kg or less), S/V (ca. 8-35 Wh/liter or less) and S/M (ca. 6-15 Wh/Kg or less) and charge and energy retention (both RC and RE typically ≤50% retention after 30 days after charging, and typically ≤10% after 180 days after charging) as well as relatively high initial cost per unit performance as well as overall lifetime cost.
Accordingly, there remains room for improvement and variation in the art of energy storage apparatuses, including supercapacitors and hybrid capacitors, leaving an unmet need for devices offering a superior combination of any or all of these missing performance characteristics.